December 2004 • January 2005 • Vol. XXIII No. 2 • An Arnold Publication

Flexible QA
A Major Silicon Valley Manufacturer Switches to 
Flexible QA to Service Its Flexible Manufacturing Systems.

Story and photos by C. H. Bush, editor

Here’s a real, if somewhat unpleasant, mathematical problem. Subtract most of the high-volume, easy-to-produce, traditional machine-shop work from the U.S. metalworking market. Now take those projects overseas to countries with workers earning near slave-labor wages, and what do you have left?

“The answer is a market demanding more and more complex machining in low volumes, combined with assembly and inspection services, and all done at highly competitive prices,” says Zach Taylor, CEO at Fremont, CA’s D&H Manufacturing Company. “Which is exactly what we offer at D&H, complex integrated solutions. We’re a true contract manufacturer, specializing in machining, assembly and testing.” 

In spite of the giant sucking sound of traditional work rushing offshore as noted by many business people, D&H is one of the most successful shops in the country. It has 152 employees operating from a 100,000-sq-ft facility filled with equipment that could qualify for a niche in the hall of giants.

In addition to a huge lineup of standalone lathes and mills, the company currently operates 3 Niigata horizontal FMS with more than 100 pallets, with a significant potential for further growth. Two of the cells are fed by 48 pallets. The other is a 6-machine FMS cell serviced by 58 pallets in a new facility designed specifically to accommodate such equipment. 

“With our setup we can compete with offshore,” Taylor says, “but only if our customers look at the landed cost of their products, not just price per widget. That cost includes out-of-spec products, quality issues, the cost of shipping materials overseas and back, a lot of issues. We try to develop strong customer relationships, so we can help them analyze that landed cost. One of our goals is to remain at the cutting edge in technology so we can stay competitive enough to equal or beat that landed cost.”

Lean Manufacturing Environment

Lean manufacturing is the name of the game, according to Taylor. 
“In today’s market the only thing we really can offer is a lean environment,” he says. “Our customers want low volumes, high quality and low prices, and we can’t afford to keep big inventories. To meet their needs, we’ve had to make the switch from traditional to just-in-time and that means maximization of these flexible systems. We’ve come a long way with our current setup, but the truth is we’ve only taken the first steps toward where we want to be. We still have a long way to go.”
In order to remain competitive, Taylor says it is essential to produce more with less people.

“Our goal is to eliminate as much labor content as possible,” he explains. “If you want to survive, you can no longer have one man per machine. You have to spread your labor over multiple machining centers. For our flexible systems we set the bar at running twenty-four-seven. To do that, you have to have offline programming and you have to keep a queue of jobs ready to be loaded while you’re preparing for new products. You also have to plan for first article testing. We have our own custom software laid over the Niigata package. Together they give us the data we need down to the pallet level. We can tell you what’s going to run on any of our pallets at any time on any night next week or next month. It’s really amazing.”

Just-In-Time Pressures QA

D&H mostly serves customers in the defense and semiconductor industries. As a result, quality control is critical for the ISO 9002-certified company. 

“In the old days, our inspectors could check a part, give it back to manufacturing, and our machines might spend three days running just that part,” Taylor says, “but we can’t do that anymore. Nowadays, you can’t even run a day’s worth of inventory. What it boils down to is that you have to be able to check a part fast, and then run three of them for your customer. Just-in-time manufacturing puts tremendous pressure on inspection to turn out parts fast. So, in order to keep up with our automated manufacturing, we had to find a way to remove the labor bottleneck from the inspection process.”

Taylor says D&H is able to program its systems to produce other parts while they’re waiting on inspection, but even so, with tight customer delivery demands, the old inspection turnaround parameters didn’t cut it.

“The bottom line was we had a high-speed, flexible manufacturing system in place,” he says. “and we needed high-speed, flexible inspection to go with it.”

Brown & Sharpe Global Image

To meet the demand for rapid part verification, D&H purchased a Brown & Sharpe Global Image automated CMM driven by PC-DMIS software. In order to handle their parts, which range in size from a shoe box to a small conference table, the company bought a system with a 1200 x 2200 x 1000-milimeter work envelope. Senior inspector/programmer John Heal, a 6-year D&H veteran, was assigned to get the new system up and running. 

“My goal was to duplicate in inspection what we were doing on the floor with the Niigatas,” Heal says. “In the shop you do offline programming, then you have operators who load the tombstones and push a button. The way I saw it was that, if a machining center could be run that way, so could the Global Image. We wanted to treat the CMM as if it were a CNC machining center.”

Heal also wanted an inspection system he could teach to virtually anyone, quickly and easily. 

“That meant I had to have the programming done for the parts and an easy way for the inspector to know how to set up the machine for the part,” he says. “What I didn’t want was for me or another programmer to be stuck in the middle, answering a lot of questions. What I wanted was a system that allows programmers to spend their time programming new parts while the inspectors, just as their counterparts do on the floor, get their work done without us.”

Flexible QA

In the past most of the emphasis in research and development had been in the manufacturing area, Heal says, while inspection had been left to play catch up.

“Now, though, we finally have what we need to fully automate,” he says. “With the Global Image and PC-DMIS we have the equipment and software to keep up.”

In spite of the software’s power and flexibility, it took Heal several months to get the system up and running the way he wanted it.
“That was because we had so much to learn about the hardware and the software,” he says, “plus we had no history in inspection to use as a road map to where we wanted to go. We developed the system we now have by trying different approaches until we got it right.”

Heal’s current system is as simple and straightforward as that used in the shop.

“Each part comes to us with a job traveler and a part number,” he says, “so the first thing we do is create a program file which has the same number as the part. Next we write the inspection program. Included in the file are detailed instructions the inspector needs to run the part, including where to put the stops on the CMM.”

To be sure the part is set up right, Heal creates a digital video and includes that video in the inspection program.

“This is a very useful feature of the PC-DMIS software,” he says. “When the inspector pulls up the program, he gets complete instructions, and a step-by-step video showing how to set up the part on the CMM. All the inspector has to do is put the part against the stops, hit a green button and the machine is off and running. One of the best features is that the software warns the inspector if the part is out of spec. It shows a red histogram if the part is out of spec and a green one if it’s okay. Because the system is so easy to use, I can take anybody with common sense and teach them to be an inspector in a very short time.”

To be sure the part is in the proper location, Heal programs in a specific feature to guarantee the part is loaded correctly. 
“I measure a unique feature on the part, usually a circle,” he says. “The machine checks out that feature, and if it’s okay, you know the part is properly located and oriented. Before we pass on a program, the inspectors run it at 20% of full speed and watch it for any problems. That way we know it works before we crank it up to full speed.”

Results So Far

How has the new flexible system worked so far?

“Actually, the results have been amazing,” Heal says. “We’ve doubled our output with half the people. We’re inspecting the output of fifteen high-speed horizontal machining centers and one-hundred and thirty-two pallets. Turnaround time for inspection has gone from eight hours down to forty minutes, and even faster in some cases.”

At present Heal’s department is running 2 shifts starting at 6:00 A.M. and finishing at 10:00 P.M. 

“Eventually we’ll be running twenty-four-seven just as the shop does,” he says, “but with the simplicity of our system, we won’t have any problem finding inspectors to do the work. With the Global Image and PC-DMIS, we’re ready and able to handle anything the shop can produce.

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